The phone number issue is pretty overblown since it's a clear and intentional tradeoff that allows signal to retain very little metadata (leveraging local phone contacts instead of sending your social graph to their servers like everyone else). Moxie Marlinspike is the founder/co-author of the protocol and Brian Acton put in massive funding after the FB/Whatsapp fallout - not sure you can get better than that?
They're also making moves to make the phone number requirement unnecessary. What privacy features does Telegram have? It sounds like they don't even have encryption on by default and people have also dismissed their security? Why would anyone use them?